The present invention relates to a lithium-oxygen secondary battery comprising a lithium-containing negative electrode in contact with a lithium ion conducting molten salt electrolyte and an oxygen positive electrode, wherein an oxygen ion conducting solid electrolyte effectively separates the respective half-cell reactions. Upon electrochemical charge, lithium is deposited at the negative electrode/molten salt electrolyte interface and oxygen gas is evolved simultaneously at the positive electrode.
In theory, the lithium-oxygen couple should provide an electrolytic cell having one of the highest energy densities yet investigated for advanced battery systems. It has not been possible previously to achieve high electrochemical reversibility at both electrodes under cell operating conditions providing reasonable cell efficiency and cell lifetimes.